Five years ago Bruce Bennett had never heard of sleep apnoea. He only knew that every morning he woke up feeling thoroughly washed out. Though barely 50, he thought he was getting old. Someone who had once enjoyed football, squash and gardening, he became sucked into a vicious cycle of exhaustion, inactivity and weight gain.

Soon he was 15st 7lbs, collar size 18ins and barely able to push a mower across his lawn. His nights were filled with snoring and lurid dreams. ''Sometimes I thought I was being chased by lions. When I woke up, the bed looked like a battlezone.''

His work involved frequent trips to Northampton. The 370-mile journey from his home in Dalgety Bay which had once taken him five hours, was soon lasting eight because of stops for naps to avoid falling asleep at the wheel. Severe headaches eventually drove him to his GP and, after a year-long wait, he attended Edinburgh Royal Infirmary's Sleep Centre. Doctors there diagnosed severe sleep apnoea.

During tests, Bruce, now 57, stopped breathing 72 times in one hour. Each time his brain jump- started respiration by lifting him into the twilight zone between wakefulness and the deep sleep our bodies need to survive. With the aid of a special mask that delivers a continuous stream of air down his throat, Bruce now sleeps like a baby, but thousands like him never sleep easy and continue to be a danger to themselves and others.

Last week, Halifax MP Alice Mahon launched the first bill aimed at tackling the hidden menace of sleep apnoea. Though it stands scant chance of reaching the statute book, it may help raise the profile of sleep disorders, which affect about 770,000 people in the UK. Of those, around 300,000 are thought to

suffer from sleep apnoea. Though it is now more common even than type-1 diabetes, few sufferers receive treatment and most don't even know they have the condition.

Overweight middle-aged men are most prone to the disorder, which GPs often misdiagnose as exhaustion due to overwork. As obesity increases, the number of sufferers is growing dramatically. Because they rarely wake completely, it's often their partners who raise the alarm.

Most sufferers snore. In deeper sleep the throat relaxes and narrows. In overweight people there may be so much laxity in the throat muscles that it gets sucked shut and the sleeper stops breathing for anything from 10 seconds to a minute or more. In

others it is the shape of the jaw that causes the problem, which is why it tends to run in families. Bruce, it turned out, fell into both categories.

The problem isn't new. In Pickwick Papers, Charles Dickens depicted Joe the Fat Boy who ''goes on errands fast asleep and snores as he waits at table''. Sleep apnoea wasn't recognised as a serious condition until the 1960s.

Only 5000 of the estimated 50,000 sleep apnoea sufferers in Scotland are receiving treatment, according to Dr Tom MacKay of the Edinburgh Sleep Centre. There are seven smaller clinics, including two in Glasgow, but all have long waiting lists.

''Our waiting list is two years. It's the longest NHS waiting list in Scotland. We're simply overwhelmed,'' says Dr MacKay, who sees more than 1000 new patients a year, double the figure of six years ago. That figure is bound to rise as more Scots become obese and more sufferers seek help.

The Scottish Executive has issued guidelines on the management of the condition, but without the authority of an investigation by Nice (the National Institute for Clinical Excellence), Scottish area health boards aren't obliged to prioritise treatment. The result is the usual postcode lottery. Some sleep clinics have even been threatened with closure.

There are three reasons why we should be concerned. First, sleep apnoea sufferers are a menace behind the wheel. ''People with un-diagnosed sleep apnoea are between six and eight times more likely to have a serious road accident,'' says Dr MacKay. That's mainly because they often fall asleep while driving but they are also bad drivers even when they're awake. ''We've found that on driving simulators people with sleep apnoea do worse than drunk drivers,'' reports MacKay.

Linlithgow MP Tam Dalyell is a strong supporter of Alice Mahon's 10-minute-rule bill. ''I became deeply interested in sleep apnoea as a result of a series of terrible accidents on the old A8 between Glasgow and Edinburgh where the weight of suspicion was on micro-sleep rather than drunk driving. No slogan is truer than tiredness kills,'' he said.

Brian Morris hadn't realised that he was having hardly any deep sleep and admits surviving a long journey by asking his son to skoosh a plant spray at him each time he nodded off at the wheel. ''I was always sleepy. Rumble strips have probably saved my life,'' said the 52-year-old builder from Cupar.

The condition presents a difficult dilemma to coach and lorry drivers because motorists diagnosed with sleep apnoea must by law declare it to the DVLA who may revoke their licences. Failure to do so can incur a fine of up to (pounds) 1000 under the 1998 Road Traffic Act.

That brings us to the second reason why sleep apnoea should concern us. Sufferers are liable to have accidents at work. MacKay's patients have included an air traffic controller as well as builders who have fallen off roofs after falling asleep. Those in desk jobs risk dismissal for slumbering through meetings. Employment tribunals regard falling asleep at work as grounds for dismissal.

Thirdly, as well as losing their jobs, many sleep apnoea sufferers lose their partners. ''I'm forever seeing people whose marriages have come to grief because of a constant barrage of snoring and breath-holding episodes that leave both parties exhausted and fractious,'' says Dr MacKay.

Given the scale of the problem, the most extraordinary facet of this story is that there is a cure that is both instant and cost-effective. About 3500 people in Scotland use CPAP (continuous positive airway pressure) treatment. It involves wearing a cap over the nose, linked to a simple pressurised air delivery system. This may not be romantic but it has saved the marriages, the jobs and possibly the lives of many sufferers. Research in Edinburgh has shown that the cost of treating 500 patients for five years is around (pounds) 400,000, compared with the cost of accidents caused by 500 untreated patients of (pounds) 5.3m over the same period.

MSP Christine Grahame, health committee convener, is calling for a debate on sleep apnoea in the Scottish Parliament. She wants CPAP machines to be financed via community pharmacy budgets, freeing up funds to enable sleep clinics to tackle waiting lists. ''Patients in Edinburgh are waiting 17 months for CPAP treatment. During that time they can be driving buses, lorries and trains.''

Bruce Bennett was dreading the idea of wearing a mask at night but the effect was immediate. The snoring stopped and he sank into a deep, dreamless sleep. That was nearly five years ago. ''I'm still somewhat embarrassed about putting it on. I prefer the light to be off first but I wouldn't be without it. Now I'm an evangelist for this treatment. It's given me back my life.''

For further information:

www.scottishsleepapnoea.co.uk and www.sleep-apnoea-trust.org.

Are you at risk?

what to look out for:

1. Irresistible sleepiness during

the day

2. Snoring

3. Severe headaches

4. Obesity, especially in middle-aged

men with large collar sizes

5. Sometimes jaw shape is a

factor

6. Hay fever sufferers are at

higher risk

7. Mysteriously, left-handers are

more likely to have it.